The present invention relates generally to anti-lock braking systems. More particularly, the present invention relates to the testing of anti-lock braking system in trailers and tractors.
Advances in technology have brought about great changes in the operation of braking systems in transportation vehicles. Some of these changes enable braking systems to sense current road conditions and adjust the operability of the brakes in response to these conditions. These systems have been installed on a wide range of vehicles from personal automobiles to single high-volume transportation vehicles such as buses and trucks. With the latter, a need has developed to quickly and accurately test the current condition of these braking systems especially in companies that have a large number of vehicles.
In a conventional brake system without antilock brakes, when the driver presses the brake pedal, fluid, usually oil on cars and smaller trucks and air on large trucks, is forced to the actual brake mechanism at each wheel.
The pressure from the oil forces a stationary braking surface against a rotating surface, which is attached to the wheel. Friction is induced as it slows the rotating wheel. The rotating surfaces are, respectively, drums or rotors. The slowing wheel also slows the vehicle because of friction between the tire and the road surface. A component known, as the xe2x80x9crelay valve,xe2x80x9d is a significant part of an air brake system on a trailer. This component xe2x80x9crelaysxe2x80x9d a control air pressure signal from the driver""s brake pedal in the cab to the brakes. A control line, a small diameter tube running the length of the vehicle, becomes pressurized when the driver applies the brakes. A separate source of compressed air also exists. This is the xe2x80x9cpowerxe2x80x9d air and a reserve is stored in a tank on the trailer. This power air flows to the brakes to affect the actual braking work. The relay valve isolates the control air signal from the power air.
Conventional brakes systems tend to suffer from driver-induced errors. For example, when driving on wet surfaces, excessive pressure on the brakes could force the wheels to stop rotating and eventually to lock before the vehicle stops. The vehicle does slow down, but directional control is lost, and, depending on which wheel locks, and on the road conditions, the vehicle may spin. To further complicate the problem, drivers attempt to take directional control of the car, which can further exacerbate the problem. Additional complications are dictated by regulation and failure mode considerations.
To overcome this inherent disadvantage of conventional braking systems, antilock brake systems (ABS) have been developed. The ABS is a system that prevents wheel lockup by automatically modulating the brake pressure during an emergency stop. These systems offer significant safety and control advantages and ABS is now in common use on most types of vehicles. ABS prevents wheel lock-up by controlling brake torque so that the tire to road interface makes most use of the available friction while at the same time providing a reasonable level of lateral stabilizing force. In an emergency or a panic braking situation, ABS functions by keeping the brake pressure at a level just below that which would cause the wheels to lock-up. The vehicle remains stable during emergency or panic brakingxe2x80x94that is, the vehicle does not spin. In addition, the vehicle remains steerable during emergency or panic braking. In effect, ABS utilizes the available friction between the tires and the road while ensuring that a high side force (perpendicular to the direction of travel of the vehicle) is also available, thus providing vehicle stability and steerability. Stopping distances are shorter than with locked wheel stops under most conditions. Finally, the lifetime of the tire is increased when ABS is used.
A conventional ABS includes a wheel speed sensing mechanism, an electronic control module (ECM) and a modulation system, which controls the brake actuation fluid (air for heavy trucks) pressure. The modulation system consists of one or more modulators and includes a pneumatic control module (PCM).
The wheel speed sensing mechanism, the ECM and the modulation system are additions to the conventional brake system, which, for most vehicle types, remains largely unchanged. The wheel speed sensors determine the speed of the wheels and sends this information, in an electrical format, to the ECM. The ECM analyzes the wheel speed information and, if appropriate, electrically signals the modulation system to prevent wheel lock-up. The modulation system responds to these signals and physically reduces the brake pressure to optimum level for the conditions. As noted above, the modulation system controls the brake air pressure. This control becomes active only during hard braking, and/or slick conditions, where the wheels would have stopped rotating (lock-up) in the absence of an anti-lock brake system.
As one can see, the use of ABS systems have become an integral part of the motorized transportation system. Improvement in braking is achieved using ABS systems only if the systems are operating appropriately. The operation of ABS systems must therefore be maintained and monitored. Therefore, there is a need to quickly determine the operability and status of an ABS system.
Accordingly, it is desirable to provide an apparatus that is able to determine the operability and status of an ABS system. The system needs to be discrete enough to use on multiple trailers, vehicles or cars with minimum amount of effort.
It is therefore an aspect of the present invention to provide a device that obtains the status of an anti-lock brake system of a trailer.
It is another aspect of the present invention to provide a device that obtains the status of an anti-lock brake system of a tractor.
It is another aspect of the present invention to provide a device that automatically obtains the status of an anti-lock brake system upon connection of the device to a communication medium.
It is aspect of the present invention to provide a method for obtaining the status of an anti-lock brake system of a truck tractor or trailer.
In one aspect of the invention a novel device that activates automatically upon connection to the anti-lock brake communication medium as is provided. The device for testing the status of an anti-lock brake system in a tractor trailer configuration includes a connector that links the device to a communication medium in a trailer or tractor or simultaneously to the tractor and trailer. A receiver is linked to the connector wherein the receiver detects data transmissions in the communication medium and a processor is linked to the receiver wherein the processor monitors the data transmissions at the receiver and determines whether the device is linked to either the trailer or tractor. The processor determines the status of the anti-lock brake system. The processor is activated automatically on being linked to the communication medium, which for the truck trailer or tractor is the electronic control unit (ECU).
In another aspect of the invention, the device can further includes a transmitter that is linked to the processor and transmits data through the communication medium upon detection by the processor that the device is linked to a trailer. At this point, the transmitter transmits specific codes to the truck tractor anti-lock brake system. In the preferred embodiment, the anti-lock brake system indicator light is flashed, meaning the system is operational.
In yet another aspect of the present invention, a device for testing the status of an anti-lock brake system in a tractor trailer configuration includes a means for connecting the device to either a tractor or trailer or simultaneously to a tractor and trailer, a means for detecting data transmissions in a communication medium. The means for detecting is linked to the means for connecting. Another element is a means for monitoring the data transmission received at the means for detecting, The means for monitoring is activated automatically upon connection the communication medium. The device can also be comprised of a means for transmitting in the communication medium and a means for powering that is connected to the device wherein the means for powering can be a battery.
In yet another aspect of the present invention, a method for testing the status of an anti-lock brake system in a tractor trailer configuration comprises the steps of connecting a device to a communication medium in the tractor or trailer or simultaneously to the tractor and trailer, monitoring the data transmissions in the communication medium through the device, and determining from the data transmission if the device is connected to a tractor or trailer or both and determining the operability of the anti-lock brake system. The device activates automatically upon connection to the communication medium.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.